NFL Network Insider Ian Rapoport reported the move on Tuesday but the transaction could not be made official until Wednesday at the start of the new league year.

Agreed to terms with @casekeenum7 on a two-year deal. Heâs a great fit for us and is coming off a tremendous season. Excited to add Case's leadership, competitiveness and experience! pic.twitter.com/8uvbi4G6Mt

Instead of fully jumping into the Kirk Cousins sweepstakes, Elway made sure that he had a starting quarterback in place well before free agency started.

Keenum is coming off a career-altering season in Minnesota, having helped the Vikings reach the NFC Championship Game after Sam Bradford was lost in September to a knee injury. But Vikings coach Mike Zimmer never fully committed to Keenum publicly as the team's long-term option, whether during the season or after it ended.

"Is Case the guy he was last year or is he the guy he was two years ago?" Zimmer asked last week at the NFL Scouting Combine.

The Broncos are clearly betting on the latter, possibly with some belief that Keenum could look like the guy he was with the Houston Texans back in 2013. Keenum started eight games that season, which wound up being Gary Kubiak's final year as head coach in Houston. Kubiak, who won a Super Bowl as Broncos coach, has since taken on an expanded role in the Broncos' front office this offseason. Surely his experience working with Keenum added to the Broncos' comfort level in bringing Keenum on board despite the 30-year-old's risk-taking style.

Keenum will be joining his fourth team in five seasons, which virtually defines "journeyman." That's why it's somewhat ironic he wound up being the first domino to fall in an offseason that will be defined by quarterback movement. And there's no guarantee he's the last big move that Elway makes at the position.

The Broncos hold the fifth-overall pick in April's draft and Keenum would make some sense as a "bridge quarterback" to the next great hope in Denver. It's also possible that Elway is holding out hope his last first-round pick at quarterback, Paxton Lynch, develops behind Keenum.

After two seasons in quarterback purgatory, Elway didn't want to wait for the rest of the market to make his move. The Broncos executive said in January that people don't understand how "miserable" a 5-11 season is, especially for a proud franchise like the Broncos which hasn't experienced back-to-back losing seasons since the early 1970s.

Elway surveyed the field and decided that Keenum was the right choice to reverse Denver's course and keep that remarkable streak going. Forever a backup, Keenum was essentially the starting quarterback for this free-agent period.